C'mon, Jim. How many people do you think want to return to subsistence living even if they could get access to land.
None of the technological advances of the past have ended up hurting the economy.
One more reason we need to spread beyond the earth. The periods of greatest economic growth are directly tied to the growth of mankind overall.
We naturally look at something like asteroid mining as a spectacularly skilled and specific job and it is only because it isn't common. In 100 years it may be as common as being a construction worker. Still skilled labor but not as out of reach as being an astronaut is today. Society as a whole learns and becomes acclimated to the technology around us.
My great great grandfather was born in the 1870s but by the end of his life in the 1950s he had flown a DC3 or whatever was the common passenger plane of the period. He began his life plowing fields with a horse and an ox and by the end he flew a plane in an era where flight had become common. He was able to do so because the technology was born and evolved around him.
His daughter, my great grandmother was the same way. She saw great technological advances in her lifetime (1900 to 1996) but in the 20 years since her death the tech has advanced so much that it would be alien to her. If I were to travel back to 96 and hand her my smart phone she would probably use it as a coaster and put a coffee cup on it. However I wouldn't have been much more adept at using the tech then.
Here I am today and I'm completely comfortable with a smart phone or computer and I've never taken a lesson.